Review on High Temperature HVAC Aluminum Foil Tape - 2 Inch By 210 Feet (70 Yards) 3.6 Mil - Ideal For Sealing & Patching Hot/Cold Air Ducts, Metal Repair, And More - Professional Grade Quality! by David Citizen

I've been using Aluminum Tape for years for many applications and this one is the best one I've ever found. It sticks to just about anything, is plenty thick, and is easily separated from it's paper backing. The aluminum is 3.6 mils thick (a "mil" is a thousandth of an inch -- NOT a millimeter as implied by the information on the Ebay page) which means that the aluminum is strong, but will easily conform to any shape and hold its shape indefinitely. The 2" roll weighs in at 1.75 pounds (the 3" roll is a hefty 2.64 lbs.) which means you're getting a lot of metal for your buck. If you need Aluminum tape, this is the one to get.